1. Field of the Invention
This invention relates to a method for decomposing a gaseous aliphatic halide compound and a decomposing apparatus employed therefor.
2. Related Background Art
With development of industrial technology in the recent years, a tremendous amount of aliphatic hydrocarbon halide compound (for example, ethylene chloride, methane chloride or the like) is used, its waste treatment becomes a serious problem. In addition, these used gases cause environmental problems such as contamination of natural environment, and numerous efforts are made for its solution. A specific treatment method is described as follows: For example, as a method for decomposing ethylene chloride using an oxidizing agent or a catalyst, there has been known an ozone decomposition method (Japanese Patent Application Laid-Open No. 3-38297) or an ultraviolet-ray irradiation method under the existence of hydrogen peroxide (Japanese Patent Application Laid-Open No. 63-218293) and the like. In addition, there is suggested use of sodium hypochlorite as an oxidizing agent (U.S. Pat. Nos. 5525008 and 5611642). In addition, there has been proposed a method for combining a sodium hypochlorite and ultraviolet-ray irradiation with each other (U.S. Pat. No. 5582741). Further, there has been known a method for suspending a photo catalyst and a liquid-like ethylene chloride consisting of semiconductor oxide particles such as titanium oxide under alkali conditions, and decomposing them by light emission (Japanese Patent Application Laid-Open No. 7-144137).
In addition to the foregoing, a photo-decomposition method for causing ultraviolet rays to be irradiated in a gas phase without using an oxidizing agent has already been attempted. For example, there has been proposed a method for ultraviolet-ray irradiation treatment of an exhaust gas containing an organic halogen compound to make an acidic decomposition gas, and then, rinsing the gas with an alkali to make it harmless (Japanese Patent Application Laid-Open No. 62-191025); an apparatus for applying air ventilation and air seasoning to exhaust liquid containing organic halide compound and ultraviolet-ray irradiation of a gas to be exhausted, and then, rinsing the gas with an alkali (Japanese Patent Application Laid-Open No. 62-191095) or the like. In addition, probably, as an example which is estimated as reductive decomposition, there has been known decomposition of ethylene chloride using iron powder (Japanese Patent Application Laid-Open No. 8-257570). Reductive decomposition has been reported for decomposition of PCE using silicon particles.
In spite of the foregoing prior art, any or all of these methods is not sufficiently practical in apparatus arrangement or the like required for decomposition efficiency or treatment, and there is demanded a method for efficiently decomposing a gaseous aliphatic hydrocarbon halide compound with a simpler apparatus arrangement.
The inventors held a variety of discussions for these technical demands. As a result, when light was emitted to a mixture gas of a gaseous aliphatic hydrocarbon halide compound and a gas containing a chlorine gas, the inventors found out that an aliphatic hydrocarbon halide compound is decomposed, and achieved the present invention.
An object of the present invention is to provide a method for decomposing a gaseous aliphatic hydrocarbon halide compound more simply.
Another object of the present invention is to provide a simple apparatus capable of efficiently decomposing a gaseous aliphatic hydrocarbon halide compound.
According to a first aspect of the present invention, there is provided a method for decomposing a gaseous aliphatic hydrocarbon halide compound according to one embodiment of the present invention is characterized by comprising the steps of: mixing a gaseous aliphatic hydrocarbon halide compound and a gas containing a chlorine gas; and emitting light to a mixture gas of the gaseous aliphatic hydrocarbon halide compound and the chlorine gas.
According to a second aspect of the present invention, there is an apparatus for decomposing a gaseous aliphatic hydrocarbon halide compound according to one embodiment of the present invention, capable of achieving the foregoing objects, is characterized by comprising: means for bringing a gas containing chlorine gas into contact with a gaseous aliphatic hydrocarbon halide compound in a closed space; and means for emitting light to a mixture gas of the gas in the closed space and the gaseous aliphatic hydrocarbon halide compound.